Quantifying the environmental performance of individual dairy farms - the Annual Nutrient Cycling Assessment (ANCA)

Dairy farming is characterised by extensive fluxes of nitrogen (N) and phosphorus (P): large amounts of these elements cycle via feed, manure, soils and crops. Losses and exports in the form of milk, meat and manure are compensated for by purchased feeds and fertilisers. At this moment, farmers lack accurate insight into the impact of their management on the functioning of these cycles. We therefore developed the model ANCA, based on the results of the pilot farm network ‘Cows & Opportunities’ and the experimental farm ‘De Marke’. The ANCA model quantifies the main performance indicator related to the nutrient cycles. The ANCA model is based on verifiable input data that can be collected with little effort, as the model is to be used by commercial farmers whilst being fraud resistant. The model outcomes help dairy farmers to demonstrate towards authorities and the dairy industry that they have produced their milk in accordance with sustainability standards. From 2015 onwards, ANCA will serve as a licence to produce for any dairy farm in The Netherlands with a manure surplus (about 70% of the number of farms).